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1.
Glia ; 72(9): 1674-1692, 2024 09.
Article in English | MEDLINE | ID: mdl-38899731

ABSTRACT

Spinal cord injury (SCI) can result in severe motor and sensory deficits, for which currently no effective cure exists. The pathological process underlying this injury is extremely complex and involves many cell types in the central nervous system. In this study, we have uncovered a novel function for macrophage G protein-coupled receptor kinase-interactor 1 (GIT1) in promoting remyelination and functional repair after SCI. Using GIT1flox/flox Lyz2-Cre (GIT1 CKO) mice, we identified that GIT1 deficiency in macrophages led to an increased generation of tumor necrosis factor-alpha (TNFα), reduced proportion of mature oligodendrocytes (mOLs), impaired remyelination, and compromised functional recovery in vivo. These effects in GIT1 CKO mice were reversed with the administration of soluble TNF inhibitor. Moreover, bone marrow transplantation from GIT1 CWT mice reversed adverse outcomes in GIT1 CKO mice, further indicating the role of macrophage GIT1 in modulating spinal cord injury repair. Our in vitro experiments showed that macrophage GIT1 plays a critical role in secreting TNFα and influences the differentiation of oligodendrocyte precursor cells (OPCs) after stimulation with myelin debris. Collectively, our data uncovered a new role of macrophage GIT1 in regulating the transformation of OPCs into mOLs, essential for functional remyelination after SCI, suggesting that macrophage GIT1 could be a promising treatment target of SCI.


Subject(s)
Cell Differentiation , Macrophages , Oligodendrocyte Precursor Cells , Remyelination , Spinal Cord Injuries , Animals , Spinal Cord Injuries/metabolism , Spinal Cord Injuries/pathology , Macrophages/metabolism , Remyelination/physiology , Cell Differentiation/physiology , Oligodendrocyte Precursor Cells/metabolism , Mice , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics , Mice, Inbred C57BL , Mice, Knockout , Recovery of Function/physiology , Disease Models, Animal , Tumor Necrosis Factor-alpha/metabolism , Mice, Transgenic , Female , GTPase-Activating Proteins/metabolism , GTPase-Activating Proteins/genetics , Oligodendroglia/metabolism
2.
J Am Chem Soc ; 146(30): 21061-21068, 2024 Jul 31.
Article in English | MEDLINE | ID: mdl-39039999

ABSTRACT

Aerocyanidin and amycomicin are two antibiotics derived from long-chain acids with a rare epoxy isonitrile moiety, the complexity of which renders the total synthesis of these two natural products rather challenging. How this functionality is biosynthesized has also remained obscure. While the biosynthetic gene clusters for these compounds have been identified, both appear to be deficient in genes encoding enzymes seemingly necessary for the oxidative modifications observed in these antibiotics. Herein, the biosynthetic pathways of aerocyanidin and amycomicin are fully elucidated. They share a conserved pathway to isonitrile intermediates that involves a bifunctional thioesterase and a nonheme iron α-ketoglutarate-dependent enzyme. In both cases, the isonitrile intermediates are then loaded onto an acyl carrier protein (ACP) catalyzed by a ligase. The isonitrile-tethered ACP is subsequently processed by polyketide synthase(s) to undergo chain extension, thereby assembling a long-chain γ-hydroxy isonitrile acid skeleton. The epoxide is installed by the cupin domain-containing protein AecF to conclude the biosynthesis of aerocyanidin. In contrast, three P450 enzymes AmcB, AmcC, and AmcQ are involved in epoxidation and keto formation to finalize the biosynthesis of amycomicin. These results thus explain the sequence of oxidation events that result in the final structures of aerocyanidin and amycomicin as well as the biosynthesis of the key γ-hydroxy epoxy isonitrile functional group.


Subject(s)
Anti-Bacterial Agents , Nitriles , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/biosynthesis , Nitriles/chemistry , Nitriles/metabolism , Epoxy Compounds/chemistry , Epoxy Compounds/metabolism , Molecular Structure
3.
Angew Chem Int Ed Engl ; 63(1): e202315844, 2024 Jan 02.
Article in English | MEDLINE | ID: mdl-37963815

ABSTRACT

Valanimycin is an azoxy-containing natural product isolated from the fermentation broth of Streptomyces viridifaciens MG456-hF10. While the biosynthesis of valanimycin has been partially characterized, how the azoxy group is constructed remains obscure. Herein, the membrane protein VlmO and the putative hydrazine synthetase ForJ from the formycin biosynthetic pathway are demonstrated to catalyze N-N bond formation converting O-(l-seryl)-isobutyl hydroxylamine into N-(isobutylamino)-l-serine. Subsequent installation of the azoxy group is shown to be catalyzed by the non-heme diiron enzyme VlmB in a reaction in which the N-N single bond in the VlmO/ForJ product is oxidized by four electrons to yield the azoxy group. The catalytic cycle of VlmB appears to begin with a resting µ-oxo diferric complex in VlmB, as supported by Mössbauer spectroscopy. This study also identifies N-(isobutylamino)-d-serine as an alternative substrate for VlmB leading to two azoxy regioisomers. The reactions catalyzed by the kinase VlmJ and the lyase VlmK during the final steps of valanimycin biosynthesis are established as well. The biosynthesis of valanimycin was thus fully reconstituted in vitro using the enzymes VlmO/ForJ, VlmB, VlmJ and VlmK. Importantly, the VlmB-catalyzed reaction represents the first example of enzyme-catalyzed azoxy formation and is expected to proceed by an atypical mechanism.


Subject(s)
Azo Compounds , Azo Compounds/chemistry
4.
J Nanobiotechnology ; 20(1): 56, 2022 Jan 29.
Article in English | MEDLINE | ID: mdl-35093078

ABSTRACT

Subtalar osteoarthritis (STOA) is often secondary to chronic ankle sprains, which seriously affects the quality of life of patients. Due to its etiology and pathogenesis was not studied equivocally yet, there is currently a lack of effective conservative treatments. Although they have been used for tissue repair, platelet-rich plasma-derived exosomes (PRP-Exo) have the disadvantage of low retention and short-lived therapeutic effects. This study aimed to determine whether incorporation of PRP-Exo in thermosensitive hydrogel (Gel) increased their retention in the joint and thereby playing a therapeutic role on STOA due to chronic mechanical instability established by transecting lateral ligaments (anterior talofibular ligament (ATFL)/calcaneal fibular ligament (CFL)). PRP-Exo incorporated Gel (Exo-Gel) system, composed of Poloxamer-407 and 188 mixture-based thermoresponsive hydrogel matrix in an optimal ratio, was determined by its release ability of Exo and rheology of Gel response to different temperature. The biological activity of Exo-Gel was evaluated in vitro, and the therapeutic effect of Exo-Gel on STOA was evaluated in vivo. Exo released from Exo-Gel continuously for 28 days could promote the proliferation and migration of mouse bone mesenchymal stem cells (mBMSCs) and chondrocytes, at the same time enhance the chondrogenic differentiation of mBMSCs, and inhibit inflammation-induced chondrocyte degeneration. In vivo experiments confirmed that Exo-Gel increased the local retention of Exo, inhibited the apoptosis and hypertrophy of chondrocytes, enhanced their proliferation, and potentially played the role in stem cell recruitment to delay the development of STOA. Thus, Delivery of PRP-Exo incorporated in thermosensitive Gel provides a novel approach of cell-free therapy and has therapeutic effect on STOA.


Subject(s)
Exosomes , Osteoarthritis , Platelet-Rich Plasma , Animals , Cartilage/metabolism , Exosomes/metabolism , Humans , Mice , Osteoarthritis/metabolism , Platelet-Rich Plasma/metabolism , Quality of Life
5.
Expert Opin Drug Deliv ; 21(6): 965-974, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38962819

ABSTRACT

OBJECTIVE: Dissolving microneedles (DMNs) have shown great potential for transdermal drug delivery due to their excellent skin-penetrating ability and combination with nanocarriers (NCs) can realize targeted drug delivery. The objective of this study was to investigate the impact of microneedle dissolving rate on the in vivo fate of NC-loaded DMNs, which would facilitate the clinical translation of such systems. METHODS: Solid lipid nanoparticles (SLNs) were selected as the model NC for loading in DMNs, which were labeled by P4 probes with aggregation-quenching properties. Sodium hyaluronate acid (HA) and chitosan (CS), with different aqueous dissolving rates, were chosen as model tip materials. The effects of needle dissolving rate on the in vivo fate of NC-loaded DMNs was investigated by tracking the distribution of fluorescence signals after transdermal exposure. RESULTS: P4 SLNs achieved a deeper diffusion depth of 180 µm in DMN-HA with a faster dissolution rate, while the diffusion depth in DMN-CS with a slower dissolution rate was lower (140 µm). The in vivo experiments demonstrated that P4 SLNs had a T1/2 value of 12.14 h in DMN-HA, whilst a longer retention time was found in DMN-CS, with a T1/2 of 13.12 h. CONCLUSIONS: This study confirmed that the in vivo diffusion rate of NC-loaded DMNs was determined by the dissolving rate of DMNs materials and provided valuable guidance for the design and development of NC-loaded DMNs in the future.


Subject(s)
Administration, Cutaneous , Chitosan , Drug Delivery Systems , Hyaluronic Acid , Nanoparticles , Needles , Animals , Hyaluronic Acid/chemistry , Hyaluronic Acid/administration & dosage , Chitosan/chemistry , Drug Carriers/chemistry , Solubility , Lipids/chemistry , Microinjections , Skin Absorption , Skin/metabolism , Male , Rats, Sprague-Dawley , Rats , Liposomes
6.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 42(3): 365-371, 2024 Jun 01.
Article in English, Zh | MEDLINE | ID: mdl-39049658

ABSTRACT

OBJECTIVES: This study aims to compare the accuracy of self-developed universal implant guide (SDG), 3D printed digital guide (DG), and free hand (FH) simulated implantation in the posterior tooth area of dental models. METHODS: Ten junior dentists were selected to place three implants in the 35, 37, and 46 tooth sites of the mandibular models (35, 36, 37, and 46 missing teeth) by using SDG, DG, and FH, and the process was repeated again to take the average value. Cone beam computed tomography (CBCT) was used to evaluate the global coronal deviation, global apical deviation, depth deviation, and angular deviation between the actual position and preoperative planned position. RESULTS: The coronal deviation and apical deviation of the three implant sites in the SDG group were not significantly different from those in the two other groups (P>0.05). The depth deviation and angular deviation in the SDG group were smaller than those in the DG group (P<0.05) and FH group (P<0.05), respectively. All deviations at site 37 in the SDG group were not different from those at site 35 (P>0.05), while the depth and angular deviation at site 37 in the DG group were higher than those at site 35 (P<0.05). CONCLUSIONS: The precision of the self-developed universal dental implant guide can meet the requirements of clinical posterior implantation.


Subject(s)
Cone-Beam Computed Tomography , Dental Implants , Mandible , Models, Dental , Humans , Printing, Three-Dimensional
7.
Light Sci Appl ; 13(1): 33, 2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38291018

ABSTRACT

Cavity-enhanced single quantum dots (QDs) are the main approach towards ultra-high-performance solid-state quantum light sources for scalable photonic quantum technologies. Nevertheless, harnessing the Purcell effect requires precise spectral and spatial alignment of the QDs' emission with the cavity mode, which is challenging for most cavities. Here we have successfully integrated miniaturized Fabry-Perot microcavities with a piezoelectric actuator, and demonstrated a bright single-photon source derived from a deterministically coupled QD within this microcavity. Leveraging the cavity-membrane structures, we have achieved large spectral tunability via strain tuning. On resonance, a high Purcell factor of ~9 is attained. The source delivers single photons with simultaneous high extraction efficiency of 0.58, high purity of 0.956(2) and high indistinguishability of 0.922(4). Together with its compact footprint, our scheme facilitates the scalable integration of indistinguishable quantum light sources on-chip, therefore removing a major barrier to the development of solid-state quantum information platforms based on QDs.

8.
Comput Struct Biotechnol J ; 21: 4816-4824, 2023.
Article in English | MEDLINE | ID: mdl-37841329

ABSTRACT

Confronting the challenge of persistent mutations of SARS-CoV-2, researchers have turned to deep learning methods to predict the mutated structures of spike proteins and to hypothesize potential changes in their structures and drug efficacies. However, limited works are focused on the surface learning of spike proteins even though their biological functions are usually defined by the geometric and chemical features of 3D molecular surfaces. In addition, the current used geometric deep learning methods are based on mesh representations of proteins to identify potential binding targets for drugs. However, the use of meshes has limitations and is not applicable for many important tasks in molecular biology. To address these limitations, we adopt the differentiable molecular surface interaction fingerprinting (dMaSIF) method which is based on the 3D point clouds and a novel efficient geometric convolutional layer to fast predict the interaction sites on the protein surface. The different binding site patterns for Delta, Omicron and its subvariants are clearly visualized. We find that Delta and Omicron show the similar surface binding patterns while BA.2, BA.2.13, BA.3 and BA.4 present similar ones. BA.4 possesses higher positive interaction site ratio than the others which may account for its higher transmission and infection among humans. In addition, the positive interaction site ratios of BA.2, BA.2.13, BA.3 are higher than Delta and Omicron, which are accordant with their transmission and infection rates. Hopefully our work offers a new effective route to analyze the protein-protein interaction for the SARS-CoV-2 variants.

9.
IEEE Trans Pattern Anal Mach Intell ; 45(3): 3226-3244, 2023 Mar.
Article in English | MEDLINE | ID: mdl-35503824

ABSTRACT

It is promising to solve linear inverse problems by unfolding iterative algorithms (e.g., iterative shrinkage thresholding algorithm (ISTA)) as deep neural networks (DNNs) with learnable parameters. However, existing ISTA-based unfolded algorithms restrict the network architectures for iterative updates with the partial weight coupling structure to guarantee convergence. In this paper, we propose hybrid ISTA to unfold ISTA with both pre-computed and learned parameters by incorporating free-form DNNs (i.e., DNNs with arbitrary feasible and reasonable network architectures), while ensuring theoretical convergence. We first develop HCISTA to improve the efficiency and flexibility of classical ISTA (with pre-computed parameters) without compromising the convergence rate in theory. Furthermore, the DNN-based hybrid algorithm is generalized to popular variants of learned ISTA, dubbed HLISTA, to enable a free architecture of learned parameters with a guarantee of linear convergence. To our best knowledge, this paper is the first to provide a convergence-provable framework that enables free-form DNNs in ISTA-based unfolded algorithms. This framework is general to endow arbitrary DNNs for solving linear inverse problems with convergence guarantees. Extensive experiments demonstrate that hybrid ISTA can reduce the reconstruction error with an improved convergence rate in the tasks of sparse recovery and compressive sensing.

10.
Front Med (Lausanne) ; 10: 1157099, 2023.
Article in English | MEDLINE | ID: mdl-37359021

ABSTRACT

Background: The pathophysiology of bone defects (BDs) is complex, and the treatment for bone defects, in particular massive bone defects, remains a major clinical challenge. Our study was conducted to explore the molecular events related to the progression of bone defects a common clinical condition. Methods: First, microarray data of GSE20980 were obtained from the Gene Expression Omnibus (GEO) database, where 33 samples in total were used to analyze the molecular biological processes related to bone defects. Next, the original data were normalized and differentially expressed genes (DEGs) were identified. Additionally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted. Finally, a protein-protein interaction (PPI) network was constructed and the trends of the different genes were confirmed. Results: Compared with the samples of non-critical size defects (NCSD), the samples of critical size defects (CSD) had 2057, 827, and 1,024 DEGs at 7, 14, and 21 days post injury, respectively. At day 7, the DEGs were significantly enriched in metabolic pathways, at day 14 the DEGs were predominantly enriched in G-protein coupled signaling pathways and the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway, and at day 21 the DEGs were mainly enriched in circadian entrainment and synaptic-related functions. The PPI network showed similar results. Quantitative real-time PCR (qRT-PCR) and western blot (WB) were performed to validate the partial results of sequencing. Conclusion: This study provides some clues about the molecular mechanism behind bone defects, which should contribute to scientific research and clinical treatment of this condition.

11.
Light Sci Appl ; 12(1): 100, 2023 Apr 25.
Article in English | MEDLINE | ID: mdl-37185331

ABSTRACT

Highly compact lasers with ultra-low threshold and single-mode continuous wave (CW) operation have been a long sought-after component for photonic integrated circuits (PICs). Photonic bound states in the continuum (BICs), due to their excellent ability of trapping light and enhancing light-matter interaction, have been investigated in lasing configurations combining various BIC cavities and optical gain materials. However, the realization of BIC laser with a highly compact size and an ultra-low CW threshold has remained elusive. We demonstrate room temperature CW BIC lasers in the 1310 nm O-band wavelength range, by fabricating a miniaturized BIC cavity in an InAs/GaAs epitaxial quantum dot (QD) gain membrane. By enabling effective trapping of both light and carriers in all three dimensions, ultra-low threshold of 12 µW (0.052 kW cm-2) is achieved at room temperature. Single-mode lasing is also realized in cavities as small as only 5 × 5 unit cells (~2.5 × 2.5 µm2 cavity size) with a mode volume of 1.16(λ/n)3. The maximum operation temperature reaches 70 °C with a characteristic temperature of T0 ~93.9 K. With its advantages in terms of a small footprint, ultra-low power consumption, and adaptability for integration, the mini-BIC lasers offer a perspective light source for future PICs aimed at high-capacity optical communications, sensing and quantum information.

12.
Redox Biol ; 60: 102615, 2023 04.
Article in English | MEDLINE | ID: mdl-36716673

ABSTRACT

Disruption of the blood-spinal cord barrier (BSCB) leads to inflammatory cell infiltration and neural cell death, thus, contributing to poor functional recovery after spinal cord injury (SCI). Previous studies have suggested that Sirtuin 1 (SIRT1), an NAD+-dependent class III histone deacetylase, is abundantly expressed in endothelial cells and promotes endothelial homeostasis. However, the role of SIRT1 in BSCB function after SCI remains poorly defined. Here, we report that SIRT1 is highly expressed in spinal cord endothelial cells, and its expression significantly decreases after SCI. Using endothelial cell-specific SIRT1 knockout mice, we observed that endothelial cell-specific knockout of SIRT1 aggravated BSCB disruption, thus, resulting in widespread inflammation, neural cell death and poor functional recovery after SCI. In contrast, activation of SIRT1 by the agonist SRT1720 had beneficial effects. In vitro, knockdown of SIRT1 exacerbated IL-1ß-induced endothelial barrier disruption in bEnd.3 cells, whereas overexpression of SIRT1 was protective. Using RNA-seq and IP/MS analysis, we identified p66Shc, a redox protein, as the potential target of SIRT1. Further studies demonstrated that SIRT1 interacts with and deacetylates p66Shc, thereby attenuating oxidative stress and protecting endothelial barrier function. Overall, our results indicate that SIRT1 decreases endothelial ROS production and attenuates BSCB disruption by deacetylating p66Shc after SCI, and suggest that SIRT1 activation has potential as a therapeutic approach to promote functional recovery against BSCB disruption following SCI.


Subject(s)
Sirtuin 1 , Spinal Cord Injuries , Animals , Mice , Blood-Brain Barrier , Endothelial Cells/metabolism , Mice, Knockout , Sirtuin 1/genetics , Sirtuin 1/metabolism , Spinal Cord Injuries/drug therapy , Spinal Cord Injuries/genetics , Spinal Cord Injuries/metabolism , Src Homology 2 Domain-Containing, Transforming Protein 1/genetics , Src Homology 2 Domain-Containing, Transforming Protein 1/metabolism
13.
Front Immunol ; 13: 819080, 2022.
Article in English | MEDLINE | ID: mdl-35359993

ABSTRACT

Background: Epigenetic modifications, according to emerging evidence, perform a critical role for cellular immune response and tumorigenesis. Nonetheless, the role of N6-methyladenosine modification in shaping of the glioblastoma tumor microenvironment is unknown. Methods: N6-methyladenosine(m6A) methylation patterns in GBM patients were evaluated via multiple omics analysis of 15 m6A regulators and systematically correlated with tumor immune features. For quantification of N6-methyladenosine methylation patterns of individual patients, GM-score was developed and correlated with clinical and immunological characteristics. Results: Glioblastoma has two different m6A methylation patterns that are strongly associated with TME characteristics, tumor subtype, immunotherapy response, and patient prognosis. High-GM-score is associated with an immune tolerance phenotype dominated by the IDH1 wild molecular subtype and the Mesenchymal tissue subtype, as well as a high infiltration of immune cells and stromal cells and a poor prognosis. Furthermore, despite higher immune checkpoint expression, individuals with a high-GM-score have a poorer response to anti-CTLA4 immunotherapy regimens due to T-cells dysfunctional. Low-GM-score individuals had an immunodeficient phenotype dominated by IDH mutant molecular subtypes and Proneural tissue subtypes, with less immune cell infiltration and a better prognosis. Furthermore, patients with low-GM-scores had higher microsatellite instability (MSI) and t-cell exclusion scores, as well as a better response to anti-CTLA4 immunotherapy regimens. Conclusion: This study demonstrated that m6A modification patterns play an important role in the shaping of TME complexity and diversity. The GM-score could identify m6A modification patterns in individual patients, resulting in a more personalization and efficacious anti-tumor immunotherapy strategy.


Subject(s)
Glioblastoma , Tumor Microenvironment , Adenosine/analogs & derivatives , Adenosine/metabolism , Glioblastoma/genetics , Glioblastoma/therapy , Humans , Methylation , Tumor Microenvironment/genetics
14.
Sci Adv ; 8(24): eabn7630, 2022 Jun 17.
Article in English | MEDLINE | ID: mdl-35704580

ABSTRACT

Photonic neural networks perform brain-inspired computations using photons instead of electrons to achieve substantially improved computing performance. However, existing architectures can only handle data with regular structures but fail to generalize to graph-structured data beyond Euclidean space. Here, we propose the diffractive graph neural network (DGNN), an all-optical graph representation learning architecture based on the diffractive photonic computing units (DPUs) and on-chip optical devices to address this limitation. Specifically, the graph node attributes are encoded into strip optical waveguides, transformed by DPUs, and aggregated by optical couplers to extract their feature representations. DGNN captures complex dependencies among node neighborhoods during the light-speed optical message passing over graph structures. We demonstrate the applications of DGNN for node and graph-level classification tasks with benchmark databases and achieve superior performance. Our work opens up a new direction for designing application-specific integrated photonic circuits for high-efficiency processing large-scale graph data structures using deep learning.

15.
Oxid Med Cell Longev ; 2022: 3156245, 2022.
Article in English | MEDLINE | ID: mdl-35450413

ABSTRACT

The osteoarthritis caused by trauma or inflammation is associated with severe patient morbidity and economic burden. Accumulating studies are focusing on the repair of articular cartilage defects by constructing tissue-engineered cartilage. Recent evidence suggests that optimizing the source and quality of seed cells is one of the key points of cartilage tissue engineering. In this study, we demonstrated that Kindlin-2 and its activated PI3K/AKT signaling played an essential role in promoting extracellular matrix (ECM) secretion and ameliorating IL-1beta-induced inflammation in chondrocytes cocultured with bone marrow stem cells (BMSCs). In vivo experiments revealed that coculture significantly promoted hyaline cartilage regeneration. In vitro studies further uncovered that chondrocytes cocultured with BMSCs in the direct contact coculture system upregulated Kindlin-2 expression and subsequently activated the PI3K/AKT signaling pathway, which not only increases Sox9 and Col2 expression but also restores mitochondrial membrane potential and reduces ROS levels and apoptosis under inflammatory conditions. Overall, our findings indicated that direct contact BMSC-chondrocyte coculture system could promote chondrogenesis, and identified Kindlin-2 represents a key regulator in this process.


Subject(s)
Cartilage, Articular , Mesenchymal Stem Cells , Cell Differentiation , Cells, Cultured , Chondrocytes/metabolism , Chondrogenesis , Coculture Techniques , Humans , Inflammation/metabolism , Membrane Proteins , Mesenchymal Stem Cells/metabolism , Neoplasm Proteins , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism
16.
ACS Catal ; 12(4): 2270-2279, 2022 Feb 18.
Article in English | MEDLINE | ID: mdl-35992736

ABSTRACT

Despite the diversity of reactions catalyzed by 2-oxoglutarate-dependent nonheme iron (Fe/2OG) enzymes identified in recent years, only a limited number of these enzymes have been investigated in mechanistic detail. In particular, several Fe/2OG-dependent enzymes capable of catalyzing isocyanide formation have been reported. While the glycine moiety has been identified as a biosynthon for the isocyanide group, how the actual conversion is effected remains obscure. To elucidate the catalytic mechanism, we characterized two previously unidentified (AecA and AmcA) along with two known (ScoE and SfaA) Fe/2OG-dependent enzymes that catalyze N≡C triple bond installation using synthesized substrate analogues and potential intermediates. Our results indicate that isocyanide formation likely entails a two-step sequence involving an imine intermediate that undergoes decarboxylation-assisted desaturation to yield the isocyanide product. Results obtained from the in vitro experiments are further supported by mutagenesis, the product-bound enzyme structure, and in silico analysis.

17.
Front Cell Dev Biol ; 10: 1071550, 2022.
Article in English | MEDLINE | ID: mdl-36467414

ABSTRACT

Deep venous thrombosis (DVT) is a common medical complication in patients with lumbar fractures. The current study aimed to investigate the predictive value of neutrophil extracellular traps (NETs) in postoperative DVT formation in patients with lumbar fractures and to develop a nomogram relating clinical admission information for prediction. Patients who underwent open reduction and pedicle screw internal fixation in the treatment of single-segment lumbar fracture in the Department of Spine Surgery, the First Affiliated Hospital of Nanjing Medical University, from December 2020 to June 2022 were enrolled in this study. Baseline data and laboratory results were collected from enrollees, and the primary study endpoint event was the occurrence of DVT in patients after surgery. Multivariable logistic regression analysis was used to identify risk factors associated with higher odds of DVT after surgery. A nomogram was constructed using the results of the multivariable model. The calibration plot and receiver operating characteristics (ROC) curve were used to show the satisfactory predictive capacity of the model. Of these 393 patients who did not have DVT preoperatively, 79 patients developed it postoperatively, and 314 did not, respectively. Multivariate analysis showed that higher body mass index (BMI) (BMI between 24 and 28: RR = 1.661, 95% CI = 0.891-3.094; BMI ≤28: RR = 5.625, 95% CI = 2.590-12.217; reference: BMI <24), neutrophils (RR = 1.157, 95% CI 1.042-1.285), D-dimer (RR = 1.098, 95% CI 1.000-1.206), and citrullinated histone H3 (CitH3) (RR = 1.043, 95% CI 1.026-1.060) were independent risk factors for postoperative DVT. Using the multivariable analysis, we then constructed a nomogram to predict DVT, which was found to have an area under the curve of 0.757 (95% CI = 0.693-0.820). Calibration plots also showed the satisfied discrimination and calibration of the nomogram. In conclusion, patients with lumbar fractures with postoperative DVT had higher levels of NETs in the circulation preoperatively compared to those without postoperative DVT. Furthermore, based on BMI, D-dimer, neutrophils, and CitH3, we developed a predictive model to predict postoperative DVT incidence in these patients.

18.
Redox Biol ; 53: 102326, 2022 07.
Article in English | MEDLINE | ID: mdl-35525025

ABSTRACT

The nonunion following a fracture is associated with severe patient morbidity and economic consequences. Currently, accumulating studies are focusing on the importance of macrophages during fracture repair. However, details regarding the process by which macrophages facilitate endochondral ossification (EO) are largely unknown. In this study, we present evidence that apoptotic chondrocytes (ACs) are not inert corpses awaiting removal, but positively modulate the osteoinductive ability of macrophages. In vivo experiments revealed that fatty acid (FA) metabolic processes up-regulated following EO. In vitro studies further uncovered that FAs derived from ACs are taken up by macrophages mainly through macrophage scavenger receptor 1 (MSR1). Then, our functional experiments confirmed that these exogenous FAs subsequently activate peroxisome proliferator-activated receptor α (PPARα), which further facilitates lipid droplets generation and fatty acid oxidation (FAO). Mechanistically, elevated FAO is involved in up-regulating the osteoinductive effect by generating BMP7 and NAD+/SIRT1/EZH2 axis epigenetically controls BMP7 expression in macrophages cultured with ACs culture medium. Our findings advanced the concept that ACs could promote bone regeneration by regulating metabolic and function reprogram in macrophages and identified macrophage MSR1 represents a valuable target for fracture treatments.


Subject(s)
Fatty Acids , Osteogenesis , Chondrocytes/metabolism , Fatty Acids/metabolism , Humans , Lipid Metabolism , Macrophages/metabolism , Scavenger Receptors, Class A/metabolism
19.
Front Psychol ; 12: 782035, 2021.
Article in English | MEDLINE | ID: mdl-35140657

ABSTRACT

As the development trend of the future housing field, green housing is an effective way to reduce pollution, save energy, and promote industrial upgrading. At the same time, the green house is of great significance to change the development mode of the construction industry and promote the sustainable development of the social economy. This study proposes a comprehensive research model to examine the influencing mechanism of residents' intention to purchase green buildings. The proposed model is empirically tested using data collected from 1,338 urban residents in China. Based on logit, probit, and ivprobit models, factors such as personal characteristics, housing price, and the number of real estate ownership are selected to conduct empirical analysis and mechanism analysis on willingness that affects consumers' purchase of green houses. The results show that housing assets significantly affect the willingness of householders to pay for green houses. The more houses they own, the higher their willingness to pay for a green house will be. Similarly, if the housing prices are higher, householders are more willing to buy a green house. The amount of housing assets will affect the willingness of householders to pay for green housing through the way of individual happiness. In terms of the characteristics of the householder, if the householder is more educated, unmarried, his willingness to buy a green house will be stronger, and owning housing assets may affect the individual happiness due to the housing wealth effect brought by rising housing prices. People with more housing assets are more likely to have the happiness brought by higher wealth, which may affect the purchase intention of householders.

20.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 27(3): 753-757, 2019 Jun.
Article in Zh | MEDLINE | ID: mdl-31204927

ABSTRACT

OBJECTIVE: To analyze the expression level of the serum soluble E cadherin (SE-CAD) and Matriptase and its clinical significance for evaluation of the disease condtions and prognosis in patients with acute myeloid leukemia (AML). METHODS: One hundred and ten patients diagnosed as AML in our hospital were divided into 3 groups: newly diagnosed group (38 cases), remission group (40 cases) and recurrence group (32 cases). The expression levels of serum matriptase were detected by Western blot, and the expression levels of serum SE-CAD were detected by ELISA. The serum levels of serum SE-CAD and matriptase among 3 groups were compared. Followin-up for one year, according to the outcome of patients, all the patients were divided into 2 groups: the survival group and death group. The serum levels of SE-CAD and Matriptase were compared between 2 groups. The correlation of serum levels of SE-CAD and matriptase with the survival of AML patients was analyzed by multivariate Logistic analysis. The evaluation value of the serum levels of SE-CAD and matriptase for the prognosis of the patients with AML were analyzed by receiver operating characteristic curves (ROC). RESULTS: The serum levels of SE-CAD and matriptase were siginificantly different among 3 groups (P<0.05). The serum levels of SE-CAD and matriptase in remission group were lowest (P<0.05), and the serum levels of SE-CAD and matriptase were not different between newly diagnoses and recurrence groups (P>0.05). Multivariate Logistic analysis showed that the serum levels of SE-CAD and matriptase were independent risk factors for the prognosis of AML patients (OR=3.157, P<0.05, OR=2.426, P<0.05). By follow-up for 1 year, the serum expression levels of SE-CAD and Matriptase in survival group were lower than that in death group. ROC curve showed that when the cut-off value of matriptase level was 0.73 and SE-CAD level was 3.42 ng/ml, the AUC of predictions for the poor prognosis in AML patients was 0.849 (P<0.05), the sensitivity was 85.6% (95%CI: 0.810~0.924) and specificity was 89.6% (95%CI: 0.849~0.941). CONCLUSION: The serum levels of SE-CAD and matriptase can perfectly evaluate the condition and short-term prognosis of the patients with AML.


Subject(s)
Leukemia, Myeloid, Acute , Cadherins , Humans , Prognosis , Serine Endopeptidases
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